Quaternary ammonium borates are compounds useful in the textile fabric softener art, and are disclosed in U.S. patent application Ser. No. 190,550, filed by Richmond et al., on Sept. 28, 1980, and entitled, "Alkoxylated Quaternary Ammonium Borates." A typical method for manufacturing the compounds disclosed therein comprises treating an amine with boric acid, and then treating the resulting mixture with an alkylene oxide. This process is generally suitable for manufacturing the instant compounds, but is unsatisfactory in some respects. If the amine remains in its free state rather than being quaternized to the quarternary ammonium borate, the resulting compound is less efficacious as a fabric softener or in other applications. A stoichiometric excess of ethylene oxide is required to ensure an adequate conversion of the free amine to the quaternary product. However, the excessive use of ethylene oxide itself increases the production of undesirable side products, such as the carcinogenic dioxanes. Another disadvantage of the above method is the relatively slow reaction rate, which in itself increases dioxane levels and also increases production costs. Finally, the above method results in a compound having a Gardner color of 5 or more. A quaternary compound having a lower Gardner color is preferable in that it can be mixed with inactive ingredients to yield a commercial fabric softening formulation having a desirable light pink or blue color whereas a quaternary having a high Gardner color must first be bleached with a peroxide to lower the color to within the preferred range before mixing with the inerts.
Processes for manufacturing other quaternary ammonium compounds said to be useful as antistatics are described in U.S. Pat. No. 2,897,170, issued to Gruber on July 28, 1979, and entitled "Antistatic Treatment with a Quaternary Ammonium Compound containing a Polyetheneoxy Grouping and Products Thereof," and in U.S. Pat. No. 4,139,477, issued to Hayek et al. on Feb. 13, 1979, and entitled "Fabric Conditioning Compositions." Gruber discloses a quaternary ammonium compound that is typically prepared by mixing a tertiary amine with ethylene oxide and an anion containing acid in the presence of a solvent such as water. More specifically, the heated tertiary amine is dissolved in a secondary or tertiary alcohol and to the resulting solution is added from 40 to 80% of the theoretical quantity of acid required for complete neutralization of the amine. The resulting solution is heated to reflux and ethylene oxide is added at such a rate that moderate reflux takes place. This reaction may require as long as eleven hours to complete, and the method does not disclose the use of a diol as a reaction rate enhancer. In addition, Gruber does not disclose ethoxylated quaternary ammonium borates.
Hayek discloses an ethoxylated quaternary ammonium compound that is typically prepared by combining hydrogenated tallowamine with ethylene oxide and then heating the reaction mixture for about 10 hours. The polyoxyethylene chains are extended by adding a 50% dispersion of sodium hydride in mineral oil and additional ethylene oxide. After addition of glacial acetic acid to neutralize the sodium hydroxide formed in the reaction, dimethyl sulfate is added to produce a quaternary ammonium methyl sulfate salt. Finally, a mixture of saturated alcohols and the codistilling hydrocarbons, as derived from alcohol manufactured by ethylene polymerization, is added to the quaternary ammonium methyl sulfate salt. The composition thus prepared has a Gardner color of 5; no diol is used in its preparation.